This invention relates to a method for analyzing the performance of a production well. In particular, the invention relates to a method for determining well productivity and skin damage utilizing pump runtime and downtime data.
Pumping wells are generally older wells with declining production. They are prime candidates for estimation of skin damage, fracture length, reservoir pressure, effective permeability, and other diagnostic information provided by pressure buildup curves. However, the necessity of removing the rods and pumps to place the conventional pressure gauge downhole and then measure pressure versus time, is an expensive process and rarely performed on a low producing well.
For the foregoing reasons, there is a need for a method which estimates well productivity during production.